The invention relates to gene targeting.
Gene targeting is a process whereby a specific gene, or a fragment of that gene, is altered. This alteration of the targeted gene may result in a change in the level of RNA or protein that is encoded by that gene, or the alteration may result in the targeted gene encoding a different RNA or protein than the untargeted gene. The targeted gene may be studied in the context of a cell, or, more preferably, in the context of a transgenic animal.
Transgenic animals are among the most useful research tools in the biological sciences. These animals have a heterologous (i.e., foreign) gene, or gene fragment, incorporated into their genome that is passed on to their offspring. Although there are several methods of producing transgenic animals, the most widely used is microinjection of DNA into single cell embryos. These embryos are then transferred into pseudopregnant recipient foster mothers. The offspring are then screened for the presence of the new gene, or gene fragment. Potential applications for transgenic animals include discovering the genetic basis of human and animal diseases, generating disease resistance in humans and animals, gene therapy, drug testing, and production of improved agricultural livestock.